Device for the texturization of synthetic thermoplastic continuous fibers

ABSTRACT

Apparatus is described for texturizing synthetic thermoplastic continuous filament yarns, consisting essentially of two hollow coaxial cylinders, one inside the other, of which the outer one is fixed and provided on its inside wall with a special guiding groove, while the inner cylinder is rotatable and provided on its outer wall, and parallel to its axis, with slots within which hooks are freely slideable, the base of the hooks fitting in the guiding groove of theouter cylinder, and whose motion depends on the configuration of said guiding groove. The guiding groove is in the form of two circular arcs perpendicular to the axis of the two cylinders, and located at different levels and communicating to each other by oblique connecting flutes. The base of the hooks is inserted into the guiding groove while the opposite yarnengaging end of the hooks is crooked or bent. The hooks are kept in the slots by both the inner wall of the fixed cylinder and a spring housed in an annular cavity around the outer wall of the inner cylinder.

United States Patent [1 1 Caroglio [4 Nov. 25, 1975 DEVICE FOR THETEXTURIZATION OF SYNTHETIC THERMOPLASTIC [73] Assignee: Montedison FibreS.p.A., Milan,

Italy 22 Filed: Oct. 25, 1973 211 Appl. No.: 409,594

[30] Foreign Application Priority Data Oct. 27, 1972 Italy 31029/72 [52]US. Cl. 28/1.8 [51]. Int. Cl. D02G 1/14 [58] Field of Search 28/1.8,72.15; 66/9 A, 66/57 [56] References Cited UNITED STATES PATENTS1,443,999 2/1923 Merli et a1. 66/9 A 2,696,034 12/1954 Swartz 28/1.82,812,569 11/1957 Lawson et al.. 28/1.8 3,022,545 2/1962 Wylde 28/1.8 X3,256,134 6/1966 Rice 28/l.8 X

3,335,475 8/1967 Hole 28/l.8 3,435,636 4/1969 Lindner et a1. 66/57Primary Examinerl .ouis K. Rimrodt Attorney, Agent, or FirmStevens,Davis, Miller & Mosher [57] ABSTRACT Apparatus is described fortexturizing synthetic thermoplastic continuous filament yarns,consisting essentially of two hollow coaxial cylinders, one inside theother, of which the outer one is fixed and provided on its inside wallwith a special guiding groove, while the inner cylinder is rotatable andprovided on its outer wall, and parallel to'its axis, with slots withinwhich hooks are freely slideable, the base of the hooks fitting in theguiding groove of theouter cylinder, and whose motion depends on theconfiguration of said guiding groove. The guiding groove is in the formof two circular arcs perpendicular to the axis of the two cylinders, andlocated at different levels and communicating to each other by obliqueconnecting flutes. The base of the hooks is inserted into the guidinggroove while the opposite yarn-engaging end of the hooks is crooked orbent. The hooks are kept in the slots by both the inner wall of thefixed cylinder and a spring housed in an annular cavity around the outerwall of the inner cylinder.

6 Claims, 4 Drawing Figures Nov. 25, 1975 Sheet 1 0f 2 US. Patent US.Patent Nov. 25, 1975 Sheet2of2 3,921,268

DEVICE FOR THE TEXTURIZATION OF SYNTHETIC THERMOPLASTIC CONTINUOUSFIBERS The present invention relates to a texturization device forthermoplastic continuous filament yarns and the relevant texturizingprocess.

More particularly, this invention relates to a device for imparting aregular wavy structure, essentially in one plane, to syntheticthermoplastic continuous filament yarns such as those based onpolyamides, polyesters, etc.

Various crimping devices for continuous filament yarns have already beensuggested in the prior art. These devices are based on thermal andmechanical treatments. The various prior art devices thus suggesteddiffer from each other essentially in the way by which the crimping ofthe filament yarn is obtained. For this purpose various expendients havebeen suggested, such as that of passing the yarns between two rollers orgears, or between two series of thin blades, of which at least one isgiven an alternating motion, and interpenetrating each other so as toforce the yarn to follow a winding path within the zone of multualinterference where consequently the crimping takes place. These devicesin practice, however, did not prove to be free of drawbacks, mainly dueto their structural complexity and their complicated maintenancerequirements. Moreover, with such devices satisfactory filament yarnsare obtained only when operating at such low production rates as to behardly remunerative, i.e. of little economical significance. In fact,the attempt to achieve high production rates with these prior artdevices results in an inordinately high production of faulty filaments,due to the excessive number of broken fibers. 7

The texturization device which is the object of this invention, on thecontrary, displays a great constructional simplicity and allows the highspeed conversion of parallel continuous filament yarns made fromsynthetic polymers into yarns having a wavy structure essentiallyarranged within one plane, without giving rise to the previouslymentioned drawbacks of the prior art devices.

The texturization device of the present invention consists essentiallyof two hollow coaxial cylinders, one inside the other. Of these, theoutside cylinder is fixed and is provided with a special guide on itsinside wall. The inner cylinder is movable and is provided on its outerwall, and parallel to its axis, with slots in which are disposed somefreely moveable hooks whose base is inserted into the same special guideof the outer cylinder. That special guide may take the form of a grooveshaped like two arcs of two circles which are perpendicular to the axisof the fixed outer cylinder, and which are arranged on different levels(i.e., displaced from each other along the axis of the fixed outercylinder) and communicating with each other by two oblique connectingsections.

The dimensions of the hooks are appropriately correlated to those of theslots of the inner cylinder and to the size of the special, guide on.the inside wall of the outer cylinder. In fact, the hooks must be soconstructed and arranged as to move freely with a rectilinearalternating motion inside the slots within which they are disposed andmust slide freely along the special guide. Moreover, the length of thehooks is appropriately correlated to the difference in height betweenthe two rectilinear sections of the special guide and to the length ofthe slots, in such fashion that when the base of the hooks is insertedin the lower part of the special guide (i.e., nearer the base of thefixed outer cylinder), they are disposed completely within the slots;while, when the base of the hooks is inserted in the upper part of thespecial guide (i.e., more removed from the base of the fixed outercylinder), the curved upper part of the hooks projects completelyoutside the slots. Moreover, the hooks are curved or crooked at theirupper ends so as to catch the yarn feed into and through the device. Theyarn thus captured by the hooks is then dragged along by the hooksduring their rectilinear retreating or reciprocating motion as the innercylinder rotates. and thereby arranges itself between the crooked endsof the hooks and the projections of the slots of the inner cylinder,thus finally tak ing up the desired sinuous shape which is thereafterheat-set to produce the texturzized yarn product.

In this way one obtains a wavy or texturized yarn whose frequency ofundulation depends on the number of hooks that operate per unit lengthon the outer circumference of the inner cylinder and whose wave heightdepends on the difference in height between the lower end of the strokeof the hooks and the upper zone of the projections of the slots.

According to another embodiment of the device which is the object ofthis invention, the special guide can be partially or completelymovable. thereby permitting the curved upper part of all the hooks toproject completely out of the slots so as to facilitate the threadingoperations of the yarn into and through the device when starting up.

The constructional and functional features of the yarn texturizingdevice which is the object of this invention will be even betterunderstood through the following more detailed description taken withreference to the figures of the attached drawings which represent apreferred form of the device given merely for illustrative and notlimiting purposes, and in which:

FIG. 1 represents a schematic view in axial cross section of thetexturizing device;

FIG. 2 represents a schematic partial side view of the external surfaceof the inner cylinder of the device of FIG. 1;

FIG. 3 shows a schematic view of the inside cylinder of the device ofFIG. 1, partially fluted; and

FIG. 4 represents schematically the application of the device of thepreceding figures for texturizing a yarn made from syntheticthermoplastic continuous filaments.

The texturizing device under consideration consists of two hollowcylinders which are arranged coaxially with one inside the other. Theouter hollow cylinder 1 is fixed and supports by means. of ball-bearings3 a coaxial shaft 2 which is integral with the inner cylinder 4. Theinner cylinder 4 is free to turn about its own longitudinal axis thanksto the motion imparted thereto through said shaft 2 by a suitable motor,not shown.

The fixed cylinder 1 is provided on its inner wall. and perpendicularlyto its axis or generating lines, with a guiding groove 5. The guiding.groove 5 is formed by two arcs of circle DC and BA which are orthogonalto the axis or generating lines of the cylinder and which merge witheach other through two oblique connecting flutes AD and CB.

On the outer wall of the inner cylinder 4, slots 7 are provided. Theseextend in a direction parallel to the axis of the inner cylinder (seeFIG. 3). Within these slots 7 are hooks 6 freely slidable therein. Theslots 7 define projections 9 (see FIG. 3) which at their upper ends areshaped in relation to the form that one wishes to impart to theundulations of the yarn filaments. A complementarily shaped base orextension 63 of each hook 6 fits into the groove of the outer cylinder 1while the opposite end 6A of each hook is crooked or bent.

As they ride in the guiding groove 5 when the inner cylinder 4 isrevolving, the bases 6B impart to the hooks 6 an alternating rectilinearor reciprocating motion in the slots 7 in a direction parallel to thecylinder axis, in coincidence with the two oblique connecting sectionsAD and CB. The amplitude of the reciprocating motion of the hookscorresponds to the distance by which the arcs AB and DC defining (withthe connecting sections AD and CB) the guiding groove 5 are separatedalong the inner wall of the outer fixed cylinder 1.

The hooks 6 are maintained in position in the slots 7 by both the innerwall of the outer fixed cylinder 1 and a spring 8 housed in an annularcavity 10 extending circumferentially around the outer wall of the innercylinder 4. For the sake of simplicity, the annular cavity 10 is shownin FIG. 1 but not in FIG. 3.

The dimensions of the hooks 6, of the guiding groove 5, and of the slots7 are such as to allow the free alternating or reciprocating movement ofthe hooks inside said slots as well as the sliding of the base 6B ofhooks 6 inside said guiding groove 5, though without too pronouncedclearances.

Moreover, the length of the hooks 6 is conditioned by the difference inheight between the two sections DC and BA of the guiding groove 5 and bythe length of the slots 7, in the following way: When. upon the rotationof the inner cylinder 4, base 6B of the hooks 6 is inserted in the lowerpart of the guiding groove 5, that is, in the section DC, the hooks 6must be completely immersed in the slots 7 of cylinder 4 for a depththat will depend on the height of the wave one wishes to impart to theundulation of the yarn undergoing processing. When the base 68 of thehooks 6, on the contrary, is inserted in the upper part of the guidinggroove 5, that is, in section BA, then the crooked or curved end 6A ofthe hooks 6 must project completely beyond or outside the slots 7.

FIG. 1 illustrates the various positions that the hooks 6 take up duringthe rotation of the inner cylinder 4. Thus, more particularly. 6.\'represents the position of a hook 6 when its base is positioned insection DC of the guiding groove 5; 6y shows its position when its baseis positioned in section BA; while 6: shows its position when its baseis positioned in the oblique connecting sections AD and CB.

In practice, operation of the above described texturizing device is asfollows:

Once all of the hooks 6 are arranged in the slots 7 with their bases 68inserted in the guiding groove 5, the inner cylinder 4 is made torevolve, for instance in a clockwise direction, and the continuousfilament yarn to be texturized is simultaneously fed to the device. Uponreaching point B of guiding groove 5, the hooks 6 take up, as explainedpreviously, the position of full projection of their crooked or curvedends 6A from slots 7 as shown at 6y.

The yarn to be texturized, after a preliminary heating, is fed by knownguiding means into the space between the crooked or curved end 6A andthe upper end of the corresponding projections 9 of the slots 7. Thepositioning of the yarn in this manner between said ends occurs whilethe hooks 6 are in the section BA. Subsequently, during the transfer ofthe hooks 6 from point A to point D of the guiding groove 5, the yarn iscaught by the crooked or curved ends 6A and pulled downwardly. therebyassuming a wavy configuration 11a as shown in FIG. 2, between the ends6A and the projections 9.

This wavy configuration 11a is maintained over the whole are of circleof the guiding groove 5 between D and C, where in the first sectionthereof the individual filaments suffer dissymmetries in their insidestructure; dissymmetries which are set in the filaments in the secondpart of the arc of circle D-C by means ofa cooling achieved either bythe convective movements of the surrounding air or by a forced blowingin of air or other like fluids through the region of yarn travel in thetexturizing device.

In oblique section CB, the hooks 6 gradually rise to the position shownat 6 thereby releasing the undulated filament which is then conveyed bya suitable thread guide towards a yarn take-up device in conventionalmanner.

As already mentioned, the yarn to be texturized, before being fed intothe texturizing device of the present invention, is heated up to asuitable temperature. This temperature, which in general must be lowerthan the softening point of the polymer of which 'the yarn is composed,depends on various factors such as the advancing speed of the yarn, onits count, on the type of polymer that forms the fiber, etc. Thus, forinstance, in the case of a polyhexamethylendiamine adipate (nylon 6. 6)yarn or of a polyethyleneterephthalate yarn, the temperature is betweenand 240C.

The heating step is carried out by passing the yarn over a metal platewhich is heated electrically or by hot fluids, or by any otherequivalent heating means well known in the art.

FIG. 4 shows the position and arrangement of the texturizing device ofthe present invention when inserted in a drawing line for as-spun yarnsin a regular plant operation. As can be seen from the figure, thetotality of undrawn filaments 11, coming directly from a spinneret orfrom a spin-cake (not shown), is passed through a feed-roller 12 whichis provided with an idle roller 13 for separating (spacing) the coils offilaments. It is then passed over draw pin 14 made of sintered ceramicmaterial and is then taken up by a stretch-roller 15 which also isprovided with an idle roller 16, and which is revolving at a peripheralspeed greater than that of roller 12. The totality of drawn filamentsthus obtained is then heated by passing over an electrically heatedmetal plate 17, whereafter the filaments are subjected to crimping inthe crimping device 18 of this invention as shown in FIGS. l-3.

As previously indicated,.the undulation imparted to the yarn depends onthe constructional characteristics of the device of this invention. Moreparticularly:

a. the frequency of undulation depends on the number of hooks 6 that areoperating per length unit on the outer circumference of the innerrotating cylinder 4;

b. the wave height depends on the magnitude of the stroke of the hooks 6below the upper or outer zone of the projections 9; and

c. the shape of the wave depends on the form of the cross-section of thehooks 6 and of the projections 9 in the zones of contact with the yarn.

The device of this invention allows one to easily vary theabove-indicated crimping characteristics by simply replacing parts ofthe device itself.

Moreover. since the forces to which the hooks 6 are subjected during theprocessing are directed chiefly along the longitudinal axis of thehooks, the device in question is characterized by an uncommonly highresistance to the stresses imparted by the moving yarn. Similarconsiderations apply with regard to projections 9 which, being integralfor their full length with the outer wall of the inner rotating cylinder4, are capable of offering the maximum of resistance, without anydeformation, to the stresses imparted by the moving yarn.

From the foregoing description, it is quite evident how versatile is thecrimping device of the present invention with regard to the range ofcounts of the workable filaments, the simplicity of construction of themoving parts, their sturdiness and their high working speed, allcontributing to significant advantages in commercial operation.

What is claimed is:

1. Apparatus for texturizing synthetic thermoplastic continuous filamentyarns, consisting essentially of two hollow coaxial cylinders, oneinside the other, of which the outer one is fixed and provided on itsinside wall with an internal guiding groove, while the inner cylinder isrotatable and provided on its outer wall, and parallel to its axis, withslots within each of which an element ending in a yarn-engaging hook isfreely slideable, the base of each element fitting in the internalguiding groove of the fixed outer cylinder, and whose motion depends onthe configuration of the guiding groove, the guiding groove on the fixedouter cylinder being in the form of two circular arcs perpendicular tothe axis of the two cylinders, and located at different levels andcommunicating with each other by oblique connecting flutes.

2. Texturizing apparatus according to claim 1, wherein the base of thehooks is inserted into the guiding groove while the opposite end of thehooks is crooked or bent.

3. Texturizing apparatus according to claim 1, wherein the length of thehooks is correlated to the difference in level between the tworectilinear sections of the guiding groove and to the length of theslots. such that when the base of the hooks is inserted in the lowerpart of the guiding groove the hooks are positioned completely withinthe slots of the rotatable inner cylinder, for a depth which depends onthe desired wave height, and when the base is inserted in the upper partof the guiding groove the crooked ends of the hooks project completelyout of the slot.

4. Texturizing apparatus according to claim 1, wherein the fixed outercylinder supports on ball-bearings a coaxial shaft integral with therotatable inner cylinder, said shaft being driven by a motor.

5. Texturizing apparatus according to claim 1,

' wherein the hooks are kept in the slots by both the inner wall of thefixedd outer cylinder and a spring housed in an annular cavity extendingcircumferentially around the outer wall of the rotatable inner cylinder.

6. Texturizing apparatus according to claim 1, wherein the slots in therotatable inner cylinder define projections that at their upper end areshaped in relation to the form that one wishes to impart to theundulations of the yarn undergoing texturizing.

1. Apparatus for texturizing synthetic thermoplastic continuous filamentyarns, consisting essentially of two hollow coaxial cylinders, oneinside the other, of which the outer one is fixed and provided on itsinside wall with an internal guiding groove, while the inner cylinder isrotatable and provided on its outer wall, and parallel to its axis, withslots within each of which an element ending in a yarn-engaging hook isfreely slideable, the base of each element fitting in the internalguiding groove of the fixed outer cylinder, and whose motion depends onthe configuration of the guiding groove, the guiding groove on the fixedouter cylinder being in the form of two circular arcs perpendicular tothe axis of the two cylinders, and located at different levels andcommunicating with each other by oblique connecting flutes. 2.Texturizing apparatus according to claim 1, wherein the base of thehooks is inserted into the guiding groove while the opposite end of thehooks is crooked or bent.
 3. Texturizing apparatus according to claim 1,wherein the length of the hooks is correlated to the difference in levelbetween the two rectilinear sections of the guiding groove and to thelength of the slots, such that when the base of the hooks is inserted inthe lower part of the guiding groove the hooks are positioned completelywithin the slots of the rotatable inner cylinder, for a depth whichdepends on the desired wave height, and when the base is inserted in theupper part of the guiding groove the crooked ends of the hooks projectcompletely out of the slot.
 4. Texturizing apparatus according to claim1, wherein the fixed outer cylinder supports on ball-bearings a coaxialshaft integral with the rotatable inner cylinder, said shaft beingdriven by a motor.
 5. Texturizing apparatus according to claim 1,wherein the hooks are kept in the slots by both the inner wall of thefixedd outer cylinder and a spring housed in an annular cavity extendingcircumferentially around the outer wall of the rotatable inner cylinder.6. Texturizing apparatus according to claim 1, wherein the slots in therotatable inner cylinder define projections that at their upper end areshaped in relation to the form that one wishes to impart to theundulations of the yarn undergoing texturizing.